This cooperative venture is an attempt to see whether routine chemistries (SMA-12, SMA-6, and hematology series) can be used to identify individuals who abuse drugs, particularly marijuana, amphetamines, cocaine, barbiturates, alcohol, and heroin. Since many young drug abusers are poly drug abusers, it may be necessary to look at classes of drugs rather than specific ones. Drinking and drug history as well as routine chemistries have been collected upon admission to the Naval drug Rehabilitation Center. A total of 600 data sets have been collected but not analyzed. The second part of the study, which involved similar data collection on 500 similar age recruits with no history of drug abuse (including negative urine screen) will be initiated shortly.